Background: Job stress has been linked to a wide range of adverse effects on mental, physical and organizational health. Objective: The objective of this study was to determine the impact of job stress on mental, physical and social health of the underground construction workers in Sikkim. Materials and Methods: The study population comprised of tunnel workers and a comparable group of controls. Using the interview technique, data was collected using the SF-36 General Health Survey Questionnaire. Results: The study population comprised of individuals of whom more than half were below 40 years of age and was comparable to the group of controls. Majority reported good health, while poor health was reported by 22 % of the subjects under study Compared to their health status last year, 52% rated their health as somewhat worse. Majority reported that their physical health problems limited them in activities of daily life, viz., running, lifting heavy objects, participation in strenuous sports, climbing several flights of stairs, bending, stooping or kneeling and walking more than a mile, during the past four weeks. More than half of them had severe body ache in the past four weeks that interfered with both work outside home and housework. This was true for emotional problems also, which interfered with their normal social activities involving family, friends, neighbors or groups. The associations of occupational stress with physical, emotional and social life and with limitation of day-to-day activities among tunnel workers were found to be statistically significant. Conclusion: The results emphasize the importance of assessment of the effects of job stress and of fulfilling the need of underground workers for optimum preventive measures.